cairo_image_surface_create_for_data ()

Creates an image surface for the provided pixel data. The output
buffer must be kept around until the cairo_surface_t is destroyed
or cairo_surface_finish() is called on the surface. The initial
contents of data
will be used as the initial image contents; you
must explicitly clear the buffer, using, for example,
cairo_rectangle() and cairo_fill() if you want it cleared.

Note that the stride may be larger than
width*bytes_per_pixel to provide proper alignment for each pixel
and row. This alignment is required to allow high-performance rendering
within cairo. The correct way to obtain a legal stride value is to
call cairo_format_stride_for_width() with the desired format and
maximum image width value, and then use the resulting stride value
to allocate the data and to create the image surface. See
cairo_format_stride_for_width() for example code.

Parameters

data

a pointer to a buffer supplied by the application in which
to write contents. This pointer must be suitably aligned for any
kind of variable, (for example, a pointer returned by malloc).

format

the format of pixels in the buffer

width

the width of the image to be stored in the buffer

height

the height of the image to be stored in the buffer

stride

the number of bytes between the start of rows in the
buffer as allocated. This value should always be computed by
cairo_format_stride_for_width() before allocating the data
buffer.

Returns

a pointer to the newly created surface. The caller
owns the surface and should call cairo_surface_destroy() when done
with it.

This function always returns a valid pointer, but it will return a
pointer to a "nil" surface in the case of an error such as out of
memory or an invalid stride value. In case of invalid stride value
the error status of the returned surface will be
CAIRO_STATUS_INVALID_STRIDE. You can use
cairo_surface_status() to check for this.

Returns

cairo_image_surface_get_stride ()

Parameters

surface

a cairo_image_surface_t

Returns

the stride of the image surface in bytes (or 0 if
surface
is not an image surface). The stride is the distance in
bytes from the beginning of one row of the image data to the
beginning of the next row.

Since 1.2

Types and Values

CAIRO_HAS_IMAGE_SURFACE

#define CAIRO_HAS_IMAGE_SURFACE 1

Defined if the image surface backend is available.
The image surface backend is always built in.
This macro was added for completeness in cairo 1.8.

Since 1.8

enum cairo_format_t

Members

CAIRO_FORMAT_INVALID

no such format exists or is supported.

CAIRO_FORMAT_ARGB32

each pixel is a 32-bit quantity, with
alpha in the upper 8 bits, then red, then green, then blue.
The 32-bit quantities are stored native-endian. Pre-multiplied
alpha is used. (That is, 50% transparent red is 0x80800000,
not 0x80ff0000.) (Since 1.0)

CAIRO_FORMAT_RGB24

each pixel is a 32-bit quantity, with
the upper 8 bits unused. Red, Green, and Blue are stored
in the remaining 24 bits in that order. (Since 1.0)

CAIRO_FORMAT_A8

each pixel is a 8-bit quantity holding
an alpha value. (Since 1.0)

CAIRO_FORMAT_A1

each pixel is a 1-bit quantity holding
an alpha value. Pixels are packed together into 32-bit
quantities. The ordering of the bits matches the
endianess of the platform. On a big-endian machine, the
first pixel is in the uppermost bit, on a little-endian
machine the first pixel is in the least-significant bit. (Since 1.0)

CAIRO_FORMAT_RGB16_565

each pixel is a 16-bit quantity
with red in the upper 5 bits, then green in the middle
6 bits, and blue in the lower 5 bits. (Since 1.2)